Low-energy dynamic filter

ABSTRACT

A means to exploit the Dean Vortices for dynamic filtering on a macro scale intended for application in utility and industrial processes is disclosed. This method relies on an apparatus of computed construction to optimize the centripetal force and minimize the effect of gravity on the separation and effectiveness of the Dean Vortices. The method is also supported by an apparatus of construction which results in an optimized elliptical flow channel that enhances the formation and persistence of the Dean Vortices.

FIELD OF THE INVENTION

The invention described herein offers significant improvements to themethod and apparatus for the separation of fluid-suspended particulatecontaminants from, and the purification of, industrial fluids such aswastewater, where the suspended particulate may range from a colloidaldispersion to suspended solids and certain dissolved solids.

BACKGROUND OF THE INVENTION

Significant field application developments in concert with abundantanalytical research have created the basis for a novel conceptual methodand a unique apparatus for separating heterogeneous material flows intoseparate higher and lower concentrate streams using Dean Vortices asextended to consider when elements in the flow and/or the fluid havegravitationally significant masses as a result of non-uniform density ordynamic viscosity, without sacrificing the capability to successfullyseparate out suspended or neutrally buoyant materials which exhibituniform density and viscosity in dynamic flows.

Recently, significant research has been published presentingmicro-fluidity technologies exploiting Dean Vortices and the mechanismutilizing the opposing forces of hydrodynamic flow and centripetal forceas a means of condensing and separating non-homogeneous particles in afluid. There is no doubt of the importance and the value of theseemerging technologies for those applications where micro-channel flowand cellular-sized particles are manipulated with these low-energyprocesses.

Typical of these implementations are Korean Patent 10-2016-0075568 andU.S. Pat. Nos. 8,807,879 B2 and 8,208,138 B2. These micro-channelimplementations are characterized by rectangular flow channels and thelinearly increasing radius of a circular spiral, where the plane of thespiral flow is orthogonal to the force of gravity, such that theorthogonal gravitational force applies collapsing pressure to the DeanVortices across the short axis of the Dean forces.

But the interests of this disclosure target the application oflow-energy particle separation from fluid carriers as applied toindustrial and utility applications where typical fluid-suspendedparticle separation technologies involve large energy expenditures usingvarious filter media, with significant maintenance and supportrequirements that limit “continuous” operations.

This novel variation of the Dean Vortices implementation has beenrealized in full size and implemented in an industrial application wherethe process was used to successfully classify and separate at a rate ofmore than 10 tons per hour.

BRIEF SUMMARY OF THE INVENTION

The Low-Energy Dynamic Filter is a typical Dean Vortices implementationwith the enhancement of the additional consideration of thegravitational effects on the fluid and the suspended particles. Byconstructing the major axis of the spiral implementation around whichthe Dean Vortices flow to be parallel to the gravity vector, thepreferred embodiment nearly eliminates the effect of gravity on thesuspended particles at significant points in the fluid channel.

Most significant is the elimination of the distortion of the Dean Flowwhen the apparent flow characteristics of density and/or viscosity arenot uniform because of the dynamic effects of the fluid system on thesuspended particles, such that the orthogonal Dean Flow is significantlyinfluenced by the forces of gravity.

Of minor consideration is the novel apparatus which affordably creates ahigh performance boundary layer and a more optimized flow channel forthe propagation of Dean Vortices by mechanically altering thecross-sectional shape of a compliant tube. The force application couldbe static or applied dynamically which, along with a variable flow rate,could be used to optimize the application of hydrodynamic forces andcentripetal forces to selectively collect suspended or neutrally buoyantparticles in the fluid.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

FIG. 1. View 1A: Illustrates the relative-flow velocity distributions of(current state of the practice) example round straight flow

-   -   View 1B: Illustrates the relative flow velocity distributions of        (current state of the practice) round curved flow channels    -   View 1C: Illustrates 3 views of rectangular curved flow channel        with the gravitational forces orthogonal to the Dean Flow. The        top left illustration shows the single flow when velocity is        insufficient to create Dean Vortices; the top right illustration        shows the flow changed to Dean Vortices as the velocity        increases; the bottom illustration shows the apparent        centripetal force, the hydrodynamic force, the flow and the        gravitational force vectors inside the curved rectangular        channel of the top right illustration.    -   View 1D: Illustrates the novel elliptical flow channel with the        gravitational forces orthogonal to the Dean Flow tending to        collapse the separation of the two competing Dean Flow forces.

FIG. 2. Illustrates gravitational forces on rectangular (View 2A) andelliptical (Views 2E, 2F) channels with major flow axis orientedparallel or “in plane” with gravity; while gravitational forces shownorthogonal to flow in both rectangular and oval shaped flow (Views 2B,2C and 2D) illustrate forces relationships avoiding the collapse of thecross-flow Deans Vortices.

FIG. 3. Illustrates the physical configuration of the variable-radiustoroidal stack of the Low-Energy Dynamic Filter, showing in View 3A asingle stack and in View 3B a configuration of 9 plates, making afour-layer stack where each single stack shares an end plate with theneighboring stack.

FIG. 4. Illustrates the adjustable separation trimming edge of theLow-Energy Dynamic Filter. View 4A shows the trimming edge plane view;View 4B shows the trimming edge in position where the flow is directedequally between the product and waste collection channels; View 4C showsthe trimming edge in position to divert most of the flow to the wastecollection channel.

FIG. 5. View 5A is a polar plot representation of the results for thevariable radius calculation in which the value for acceleration (a) isset to 2 g's (standard gravitational units) and a constant velocity of2.5 m/s. The polar plot shows data at intervals of 5 angular degrees anddescribes a plot forming a Cartesian Oval. View 5B is the actual dataused for the plot, shown in meters, and annotated to indicate the valuesat 0°, 85°, 90°, 180°, 265°, and 270°. View 5C shows an exampleCartesian Oval with force and velocity vectors shown at θ=0° and atθ=90° for illustrative purposes.

The equations used to calculate the values for the radii r and to derivethe vectors are as follows (equations are numbered here for referencelater):(e ₁)F _(g) =F _(G)×sin(θ)

-   -   where F_(G) is the standard gravitational force in mks units and        θ is the angle between r and the centripetal force F_(C), as        shown in 5C        (e ₂)Total Force=F _(C)=(sin(θ)×F _(G))        (e ₃)Force=ma    -   where m is mass and a is acceleration        (e ₄)Total a=(v ² /r)−(sin(θ)×F _(G))    -   where v is the axial velocity for a specific r at angle θ        (e ₅)r=v ²/((Total a)+(sin(θ)×F _(G))

Using the specific values stated above (a=2 g, v=2.5 m/s, and F_(G)=9.8m/s²)(e ₆)r=(2.5)²/((2×9.8)+(sin(θ)×9.8))

Using values of θ at 5 degree intervals yields the r values in the tableof View 5B, and the polar plot of View 5A.

Reference Marking Description r Represents the radius of curvature ofthe channel. θ The angle of rotation around the toroidal flow (angle θ)F_(g0°) Gravity Force vector (F_(g)) when the radius r is chosen atangle θ = 0° F_(g90°) Gravity Force vector (F_(g)) when the radius r ischosen at angle θ = 90° F_(C0°) Centripetal Force Vector (F_(c)) whenthe radius r is chosen at angle θ = 0° F_(C90°) Centripetal Force Vector(F_(c)) when the radius r is chosen at angle θ = 90° ν_(0°) Representsthe axial velocity (ν) when the radius r is chosen at angle θ = 0°ν_(90°) Represents the axial velocity (ν) when the radius r is chosen atangle θ = 90°  43 Input channel.  44 Stack leaf compression plate cover,top.  45 Stack leaf support plate with integral cross over.  46 Stackleaf compression plate cover, bottom.  47 Outlet channel, filtered.  48Outlet channel, contaminant stream, for single stack 52.  48-1 Largestdiameter channel stack contaminant output stream in a four-layer stack52A.  48-2 First reduced diameter channel stack contaminant outputstream in a 4-layer stack 52A.  48-3 Second reduced diameter channelstack contaminant output stream in a 4-layer stack   52A.  49-4 Thirdreduced diameter channel stack contaminant output stream in a 4-layerstack 52A.  49 Flow channels, side one.  50 Flow channels, side two.  51Integrated crossover flow channel between side one and side two.  52 Asingle stack, “layer,” including flow channels one and two, supportplate with   crossover, top plate and a bottom plate.  52A A four-layerstack, where each single stack shares an end plate with the neighboring  stack.  53 Callout showing stack input channel, illustrating themovable selection edge.  54 Compression bolts.  60 Inner stack crossoverfittings  61 Largest diameter channels side one and side two.  62 Firstreduced diameter channels side one and side two.  63 Second reduceddiameter channels side one and side two.  64 Smallest diameter channelsside one and side two.  65 The geometric center of the rotationaltoroid.  66 The minimum radius point of the computational distributionof the variable radius.  67 The maximum radius point of thecomputational distribution of the variable radius. 112 The flow velocitydistribution into a straight tube. 114 Straight tube section. 116 TheReynolds or “eddy” effects of flow distribution from the drag of theboundary layer against the tubing walls to the center flow of a straightcircular tube. 122 Flow velocity distribution of a curved tube 124 Acurved tube showing internal flow distribution. 126 The Reynolds or“eddy” effects of flow distribution from the drag of the boundary layeragainst the tubing walls to the center flow of a curved circular tube.131 The distorted flow in a rectangular cross-section channel withinsufficient velocity ν to form Dean Vortices. 132 Illustrates the DeanVortices formed inside the rectangular curved channel with sufficientvelocity ν. 134 The major fluid flow vector. 136 Gravity force vector(F_(G)). 140 Centripetal Force vector within the flow chamber (F_(c)).142 Hydrodynamic Force vectors. 210 The diverter edge that can beadjusted to separate the flow across the flow channel 50 from insideedge to outside edge. 220 Indicates advancing the edge of diverter 210to the outside wall moving more of the cross sectional flow to theinside or waste collection channel. 230 Indicates advancing the edge ofdiverter 210 to the inside wall moving more of the cross sectional flowto the outside or product collection channel.

DETAILED DESCRIPTION OF THE INVENTION

The invention detailed herein addresses two issues seen in currentstate-of-the-practice apparatus through evolution and adaptation of theDean Flow analysis used to supplement the well-known Reynolds analysisof flow as applied to toroidal systems, composed of relatively smalldiameter flow channels d. The Dean Flow analysis relating the DeanNumber, the diameter of the flow channel and the radius of curvature ofthe flow channel, when (d«r) as applied here, is stated as follows:

$\begin{matrix}{D_{e} = {\frac{\left( {{Centripetal}\mspace{14mu}{forces}} \right)\left( {{inertial}\mspace{14mu}{forces}} \right)}{{Viscous}\mspace{14mu}{forces}} =}} \\{= \frac{\sqrt{\left( {\rho\frac{r}{d}\frac{v^{2}}{\left( {r/d} \right)^{2}}} \right)\left( {\rho\; v^{2}} \right)}}{\mu\left( {v/d} \right)}} \\{= {\sqrt{\frac{d}{2r}}\frac{\rho\;{vd}}{\mu}}} \\{= {R_{e}\sqrt{\frac{d}{2r}}}}\end{matrix}\quad$

Where

D_(e) is the Dean's number

ρ is the density of the fluid

μ is the dynamic viscosity

v is the axial velocity

d is the diameter of the flow channel

r is the radius of curvature of the channel

R_(e) is the Reynold's number

As shown in FIGS. 1 and 2, current state of the practice createsapparatuses that do not address issues of the dynamic flow of a fluidicsystem where the suspended and/or neutrally buoyant particles and thefluid under the influence of gravity can no longer be considered to haveuniform viscosity and density and thus enable the gravitationaldistortion and collapse of the Dean Vortices. The first issue is thatthese apparatus present the Dean Vortices in a plane orthogonal to thegravitational forces, allowing for the deformation of the Dean Vorticesand leading to their collapse. The second issue is that the shape of thechannels used in these apparatuses allows distortion in the corners.FIG. 1 View 1A (top) shows a cross sectional view of a straight sectionof a circular flow channel and the distribution of velocity vector rings112 that illustrate typical slow boundary layer flow against the wallsof the flow channel as depicted by the velocity vector distribution 112for a straight conduit; 116 is an illustration of the circular rollingeddy currents created in a segment 114 by the distribution of velocityas illustrated by vectors 112 caused by flow adhesion at the boundarylayer near the walls of the conduit.

In a curved section 124 of a flow channel, the compressed velocityvectors rings 122 and the compressed and non-uniform distribution of thevelocity vectors 122 are the result of centripetal forces in the curvedconduit. The rolling eddy currents 126 bending in their flow are theresult of the centripetal forces introduced by the acceleration of thecurve in the conduit while still exhibiting the flow rate distribution122 as a result of boundary layer adhesion. But the round conduit doesnot allow sufficient laminar flow velocity v to support stabilized DeanVortices.

The evolution of a curved rectangular cross-section distorted flow 131to stabilized rectangular cross-section distortion 132 is predicted bythe Dean Number, D_(e), when the Dean Number, as characterized by theratio of the diameter of the conduit d to the radius of curvature of thecircular or spiral path r, is much smaller than unity and there issufficient flow velocity v. A rectangular flow channel with asignificant variance between the lengths of the long and short sidesenhances the onset of the Dean Vortices and aids in their persistenceover a larger range of velocities.

The formation of Dean's Vortices orthogonal to the flow 134 is theresult of the contrasting effects of centripetal force 140 andhydrodynamic forces 142. In the current practice, this phenomenon hasbeen exploited to create micro-channel membraneless filtering to isolateand collect suspended or neutrally buoyant particles where thehydrodynamic forces are balanced by the centripetal forces of therelative density and hydrodynamic drag, or resistance, for particularparticles. Of important note is that in the current practice, as shownin view 1C in FIG. 1, the gravitational force (F_(g)) is orthogonal tothe major flow vector 134 and orthogonal to the centripetal forces(F_(c)) 140 vectors and the hydrodynamic force vectors 142. Thus thegravitational force is compressing the short radius of the DeanVortices. But the current practice micro-channel implementations ofmembraneless filtering rely on the uniform viscosity and density of thefluid system, including the suspended or neutrally buoyant particles andthe fluid to limit the effects of gravity on the propagating DeanVortices.

Gravitational forces in this orientation 1C are not countered by theflow vector 134 or the centripetal force 140. As such, the centripetalforce and the hydrodynamic force of the two counter-rotating DeanVortices are subject to compression of the system of fluid and suspendedor neutrally buoyant particles, if that composite system of fluid andparticles does not move with the fluidity of a homogeneous fluid. Thisis the normal orientation of similar apparatuses found in the field ofboth research and application today and as such there are no co-alignedforces that can be manipulated to counter the disrupting effects ofgravity acting with significant leverage against the modest forces ofcentripetal acceleration and hydrodynamic flow.

It is this inventor's contention that gravitational effects haveprevented the large scale adoption of dynamic filtering for utility andindustrial applications. The unique method detailed herein benefits fromreal world empirical analysis of trial and error along with analyticalsupport in the areas that are usually taken as assumptions in bothReynolds R_(e) and Dean D_(e) analytical expressions. The methoddescribed herein rotates the major spiral or circular flow 134 tooperate in the gravitational plane.

These typical working assumptions are that the fluidic density ρ and thefluid viscosity μ are both constant throughout the flow. Suchassumptions limit the adaptation of the Dean Flow in application toparticle separation to a limited class of suspended or neutrally buoyantparticles that are not affected by the force of gravity in a dynamicflow when captured by the competing centripetal and hydrodynamic forcesof the Dean Vortices.

The method present herein specifically extends the previous method ofapplication of the Dean Vortices to the simultaneous application offluids with suspended or neutrally buoyant particles that are affectedby the force of gravity in a dynamic flow when captured between thecentripetal and hydrodynamic forces without sacrificing theeffectiveness of segregating those particles that are not affected bygravity in a dynamic flow by rotating the circular or spiral axis to bein the same plane as the gravitational vector 136.

The technique of this method is the control of the forces ofimplementation of the Dean Vortices to counter the effects of gravity.The effects available to control are the result of the centripetal forceand the fluid velocity v, which in the case of incompressible fluidscould be manipulated directly or indirectly by building flow channels ofvariable cross-sectional area; thus with constant fluid flow volumes itis possible to directly control fluid velocity.

Alternatively, the effects of velocity could be manipulated bycontrolling the centripetal acceleration, which can be realized as theangular rate, which for a constant velocity of flow is actually just afunction modifying the radius of the circular or spiral path r to createa toroidal path.

Foundational to this method is the re-orientation of the toroidal flowchannel (all views in FIG. 2) to be in the vertical gravitational planealigned with the gravity force vector such that the force of gravity isaligned with the centripetal force vector 140. Additionally, because theDean Vortices are orthogonal to the major flow 134 as the major flowmoves around the toroid, the major flow vector 134 will align with thegravitational force vector 136. Thus, the gravitational force vector isminimally disruptive because it is orthogonal to the counter-flow pathsof the two counter-rotating Dean Vortices 2E, 2F.

In these instances when the principal toroidal flow 134 is verticaleither up 2F or down 2E (angle θ is either zero or 180 degrees) andoperating either against 2F or with 2E gravity, the principal flow andthe force of gravity combine to push the forces of the Dean Vorticeseither up 2F with the principal flow against gravity or down 2E with theforce of gravity. In either direction the forces of the Dean Vorticesare not forced towards collapse. Although the vortices may be pushed toelongate their long axis and bow up or down, they are not pushed tocollapse their short axis or the separation between the twocounter-rotating vortices.

At every other point along the toroidal flow path where the sine of θ isnot zero, this method computes the radius r of the toroidal flowchannels as a function of the angle θ between the radius and the planenormal to the gravitational plane while the flow velocity remainsconstant.

The equation for Total Force (e₂) forms the basis of this method. Thecentripetal force can be varied such that the gravitational forcecomponent that is orthogonal to the long axis or working axis of thehydrodynamic 142 and centripetal forces 140 that drive the Dean Vorticeswith the result of particle separation can be countered at all anglesexcept zero and 180 degrees when the sine of θ is zero. In this example,for a given velocity (2.5 m/sec) and total centripetal force (2 g's) atable 5B of radii r can be computed where the vertical component ofgravity acting to influence the centripetal force can be countered inthe plane of interest by calculating radius r by equation (e₅) asexecuted using specific values (e₆).

While at the horizontal extremes (θ is zero or 180 degrees) where thecentripetal forces 140 cannot be used to counter the force of gravity136, the forces of gravity are operating directly against or with theforce of the major toroidal flow 134. If the fluid is not compressible,nor the flow channel significantly deformable, then the flow velocity vwill remain nearly independent of the gravitational force pushing orpulling the flow velocity vector and thus have a minimal effect on theelongation of the Dean Vortices cross-flow characteristics.

FIG. 5 includes a table (View 5B) of r values, expressed in meters,computed for a velocity of 2.5 m/sec and a continuous net centripetalforce of 2 g's. As shown in the radial plot (View 5A), the center of therotation of the toroid 65 is offset and supports radii from the minimum66 to the maximum 67 as shown on the radial graph illustrating radiifrom a minimum of about 0.21258 meters to a maximum of about 0.6377meters creating a graphical shape known as a Cartesian Oval (66, 67).

The other issue addressed by this disclosure is the shape of the flowchannel. Whereas the state of the practice employs rectangular channelsto enable the onset of the Dean Vortices, this disclosure improves uponthe rectangular cross-section channel and the inherit discontinuitiespresented by the corners of the channel to smooth flow through theimplementation of elliptical-shaped flow channels. Elliptical-shapedflow channels with significant variance between the long and shortdiameters enable the formation of Dean Vortices over a much broaderrange of flow velocities than the rectangular cross-section channel.

The preferred embodiment of this method is presented in FIG. 3 in theunique apparatus 52 of stacked plates 44, 45 and 46 and deformabletubing 43, 47, 48, 49. The deformable tubing in this implementationsupports an enhancement that aids the formation of Dean Vortices bycreating a non-circular flow channel 1D, 2C, 2D, 2E, 2F. This techniqueavoids the turbulence-inducing right-angle corners of a rectangular flowchannel. Instead, this apparatus features a compression-limitingcrossover duct fixture 51 that serves to limit the compression of theround deformable flow channel to become an elliptical flow channel 1D,2C, 2D, 2E, 2F with a significant variance between the long and shortdiameters. This configuration enhances the onset of the Dean Vorticesand aids in their persistence over a larger range of velocities.

A significant aspect of the apparatus is the optimization of thetoroidal loops with nearly ideal radial dimensions 49, 50 by stackingthem in the horizontal dimension between the compression plates 44, 45,46 and making use of the compression-limiting crossover duct 51 toseamlessly route the flow 49 to another toroidal construct 50 withidentical radial dimensions.

Also, apparatus 53 is implemented as a tunable feature of the dynamicfilter employing a movable edge 210 to select particle collections forinclusion or exclusion that may be distributed along the zero net forcepath between the opposing Dean Forces 140, 142 of the centripetal forcepushing the mass of the particles to the outside and the hydrodynamicforce pushing the hydrodynamic resistance to the inside. The mass of theparticle is pushed to the outside by the centripetal force while theresistance to hydrodynamic flow causes the suspended particles to bepushed to the inside of the channel. A particle's susceptibility tocentripetal vs. hydrodynamic flow is related to the particle's densityand physical construct as well as the principal flow velocity. The zeronet force point is the position between the outer wall and the innerwall where a particular particle's mass is pushed outward by centripetalforce to exactly match the inward hydrodynamic pressure from the counterhydrodynamic flow.

Adjusting the tunable edge incrementally towards the outside 220 or theinside 230 of the output flow channel and variation of the principalflow velocity enable this apparatus to sort or separate an extendedrange of mass vs hydrodynamic drag particles.

The assembled apparatus 52A can consist of any number of stacks 52. Asan example, 52A presents an assembly of 9 plates capturing 4 pairs ofspiral channels 61, 62, 63, and 64, each pair configured to optimumradius r for a particular channel diameter d.

Bolts 54 are used to compress the flow channels to an optimum ellipticalshape 1D, 2C, 2D, 2E, 2F. Typical input fluid channels 43 feed atdesired fluid flow velocity v. The dynamic filter of each stack 61, 62,63 or 64 of selected diameter and fluid flow velocity will separatesuspended particles to discharge through fluid channels 48-1, 48-2, 48-3and 48-4 with the remaining flow channel 47 free of an extended range ofsuspended particles separated by this configuration.

Crossover compression-limiting device 51 serves to connect the twotoroidal flows of each stack 52 and the stack cross-connecting flowchannels 60 serve to provide connections between the co-mounted stacks52 into structure 52A.

What is claimed is:
 1. A method for separating first and secondparticles in a fluid, the method comprising: introducing a plurality ofnon-homogenous particles in a fluid media into a flow circuit that isoriented to flow in a plane parallel to the force of gravity; flowingthe particles through at least one loop in a channel of the flow circuitat a velocity that causes Dean vortices to form in the at least oneloop, wherein the Dean vortices are present along an entire extent ofthe at least one loop; and separating the particles according to atleast one of a hydrodynamic drag property and a mass property bydiverting the first particles into a first flow path from the secondparticles into a second flow path after passing through the at least oneloop.
 2. The method of claim 1, wherein the channel has an ellipticalshape.
 3. The method of claim 1, wherein the channel comprises adeformable tube.
 4. The method of claim 3, wherein the deformable tubeis wound around a compression-limiting element, the method furthercomprising: compressing the deformable tube to change its shape.
 5. Themethod of claim 4, wherein compressing the deformable tube comprisescompressing the tube until Dean vortices are formed along the entireextent of the at least one loop.
 6. The method of claim 4, wherein thedeformable tube is selectively compressed to change its cross-sectionalarea according to effects of the force of gravity along the at least oneloop.
 7. The method of claim 6, wherein compressing the deformable tubeincludes compressing the deformable tube so that a section of thedeformable tube that facilitates flow in the direction of gravity has alarger cross-sectional area than a section of the deformable tube thatfacilitates flow against the direction of gravity.
 8. The method ofclaim 1, wherein the at least one loops is non-circular.
 9. The methodof claim 8, wherein a radius of the at least one loop varies so thatcentripetal forces within the channel vary according to the orientationof the channel with respect to gravity.
 10. The method of claim 9,wherein a section of the at least one loop that facilitates flow in thedirection of gravity has a greater radius than a section of the at leastone loop that facilitates flow against the direction of gravity.
 11. Themethod of claim 1, further comprising: setting a flow diverter disposedat an end of the circuit at a zero net force position in order to dividethe two separate flow paths.
 12. An apparatus for separating particlesin a fluid media, the apparatus comprising: a flow circuit configured toflow the fluid media through a channel comprising at least one looparranged in a plane parallel to the force of gravity in order to counterthe force of gravity by varying at least one of a shape of the channeland a radius of the at least one loop; and a diverter disposed at an endof the flow circuit and configured to divert the fluid media into twoseparate flow paths, wherein the flow circuit is configured to maintainDean vortices along an entire extent of the at least one loops.
 13. Theapparatus of claim 12, wherein the channel comprises a deformable tube.14. The apparatus of claim 12, wherein the channel has an ellipticalshape.
 15. The apparatus of claim 12, wherein the at least one loop isnon-circular.
 16. The apparatus of claim 12, wherein a radius of the atleast one loop varies so that centripetal forces within the channel varyaccording to the orientation of the channel with respect to gravity. 17.The apparatus of claim 12, wherein the diverter is an adjustablediverter comprising a movable leading edge that can be moved to adjustthe two separate flow paths.
 18. The apparatus of claim 12, wherein theat least one loop is a plurality of loops consecutively arranged in theplane parallel to the force of gravity.
 19. The apparatus of claim 18,wherein the loops are arranged in a helix.
 20. The apparatus of claim19, wherein each of the loops has the same shape.